Imaging lens assembly

ABSTRACT

An imaging lens assembly is provided in the present disclosure. The imaging lens assembly includes a first lens with positive refractive power; a second lens with negative refractive power; a third lens with negative refractive power; a fourth lens with positive or negative refractive power; a fifth lens with positive refractive power; and a sixth lens with negative refractive power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are arranged in sequence from the object side to the image side, and satisfy conditions provided in the present disclosure.

FIELD OF THE DISCLOSURE

The present disclosure relates to optical technologies, and moreparticular, to an imaging lens assembly applicable to a digital cameraof a mobile phone or a WEB camera, which uses CCD imaging components orCMOS imaging components with high resolution.

BACKGROUND

CCD imaging components and CMOS imaging components are used widely incamera device, to meet the requirements of miniaturization and goodperformance of the imaging components, a wide-angle lens assembly withgood optical characteristic, thin profile, and high luminous flux(namely, F number) is needed.

Japanese patent No. 5651881 discloses an imaging lens assembly includingsix lenses. However, a proportion of a total track length (TTL) and animage height (IH) of the imaging lens assembly is greater than 1.46;this is, TTL/IH≧1.46. Accordingly, the imaging lens assembly is toothick to meet the miniaturization requirement.

Accordingly, an improved imaging lens assembly which can overcome thedisadvantages described above is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiment can be better understood with referenceto the following drawings. The components in the drawing are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present disclosure. Moreover,in the drawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a schematic view of an imaging lens assembly according to anembodiment of the present disclosure, with parameter symbols labeledthereon;

FIG. 2 schematically illustrates an imaging lens assembly according tothe first exemplified embodiment;

FIG. 3 schematically illustrates the longitudinal aberration of theimaging lens assembly of FIG. 2;

FIG. 4 schematically illustrates the lateral color of the imaging lensassembly of FIG. 2;

FIG. 5 schematically illustrates the field curvature and distortion ofthe imaging lens assembly of FIG. 2;

FIG. 6 schematically illustrates an imaging lens assembly according tothe second exemplified embodiment;

FIG. 7 schematically illustrates the longitudinal aberration of theimaging lens assembly of FIG. 6;

FIG. 8 schematically illustrates the Lateral color of the imaging lensassembly of FIG. 6;

FIG. 9 schematically illustrates the field curvature and distortion ofthe imaging lens assembly of FIG. 6.

DETAILED DESCRIPTION

The present invention will hereinafter be described in detail withreference to several embodiments.

Referring to FIG. 1, an imaging lens assembly LA according to anembodiment of the present disclosure is shown. The imaging lens assemblyLA includes a lens set with six lenses, that is, a first lens L1, asecond lens L2, a third lens L3, a fourth lens L4, a fifth lens L5 and asixth lens L6, which are arranged in that order from the object side tothe image plane. A glass filter GF is arranged between the sixth lens L6and the image plane. The glass filter GF may be a cover glass or an IRfilter. Alternatively, the glass filter GF may be arranged in otherlocation or even removed from the imaging lens assembly LA.

The first lens L1 has a positive refractive power, the second lens L2has a negative refractive power, the third lens L3 also has a negativerefractive power, the fourth lens L4 may have a positive or negativerefractive power, the fifth lens L5 has a positive refractive power, andthe sixth lens L6 has a negative refractive power. In practice, the sixlenses L1 to L6 may be designed to have aspheric surfaces, so as tocompensate aberration in the imaging lens assembly LA.

The imaging lens assembly LA satisfies the following conditions (1) to(4):

0.60≦f1/f≦0.80  (1)

−2.00≦(R1+R2)/(R1−R2)≦−1.10  (2)

1.15≦(R3+R4)/(R3−R4)≦1.40  (3)

−7.50≦(R5+R6)/(R5−R6)≦−3.00  (4)

Where:

f is the focal length of the imaging lens assembly LA;

f1 is the focal length of the first lens L1;

R1 is the curvature radius of the object side of the first lens L1;

R2 is the curvature radius of the image side of the first lens L1;

R3 is the curvature radius of the object side of the second lens L2;

R4 is the curvature radius of the image side of the second lens L2;

R5 is the curvature radius of the object side of the third lens L3; and

R6 is the curvature radius of the image side of the third lens L3.

The condition (1) defines the positive refractive power of the firstlens L1. If the value excesses the minimum limit, it is better for theminiaturization of the imaging lens assembly LA; however, the positiverefractive power of the first lens L1 is too strong to compensateaberration. In contrast, if the value excesses the maximum limit, thepositive refractive power of the first lens L1 is too weak, and isadverse to the miniaturization of the imaging lens assembly LA.

In addition, the proportion value f1/f in condition (1) is preferred tobe set in the value range as defined in the following condition (1-A):

0.66≦f1/f≦0.80  (1-A)

The condition (2) defines the shape of the first lens L1. If theproportion value (R1+R2)/(R1−R2) is beyond the value range defined bycondition (2), it is difficult to compensate high order aberration suchas the spherical aberration when the imaging lens assembly LA has a lessthickness and a wider view angle with an F number (Fno) less than 2.2.

In addition, the proportion value (R1+R2)/(R1−R2) in condition (2) ispreferred to be set in the value range as defined in the followingcondition (2-A):

−1.80≦(R1+R2)/(R1−R2)≦−1.10  (2-A)

The condition (3) defines the shape of the second lens L2. If theproportion value (R3+R4)/(R3−R4) is beyond the value range defined bycondition (3), it is difficult to compensate the on-axis chromaticaberration when the imaging lens assembly LA has a less thickness and awider view angle with an F number (Fno) less than 2.2.

In addition, the proportion value (R3+R4)/(R3−R4) in condition (3) ispreferred to be set in the value range as defined in the followingcondition (3-A):

1.17≦(R3+R4)/(R3−R4)≦1.38  (3-A)

The condition (4) defines the shape of the third lens L3. If theproportion value (R5+R6)/(R5−R6) is beyond the value range defined bycondition (4), it is difficult to compensate the Lateral Color when theimaging lens assembly LA has a less thickness and a wider view anglewith an F number (Fno) less than 2.2. In addition, the proportion value(R5+R6)/(R5−R6) in condition (4) is preferred to be set in the valuerange as defined in the following condition (4-A):

−6.50≦(R5+R6)/(R5−R6)≦−3.50  (4-A)

The second lens L2 may have a negative refractive power, which satisfiesthe following condition (5):

−2.00≦f2/f≦−1.00  (5)

In the above condition (5),

f is the focal length of the imaging lens assembly; and

f2 is the focal length of the second lens L2.

The condition (5) defines the negative refractive power of the secondlens L2. If the proportion value f2/f is beyond the value range definedby condition (5), it is difficult to compensate the on-axis chromaticaberration when the imaging lens assembly LA has a less thickness and awider view angle with an F number (Fno) less than 2.2.

Upon the condition that the six lenses L1 to L6 satisfy the aforesaidconditions, the imaging lens assembly LA is possible to have goodoptical characteristic as well as an ultra-thin profile, and moreover,the imaging lens assembly LA may also satisfy the following parameterrequirements: TTL/IH≦1.35, view angle 2ω≧76°, and Fno≦2.2.

The following description describes the imaging lens assembly LAaccording to the present disclosure in detail with reference to severalembodiments; parameters of the imaging lens assembly LA are defined asfollows, in which the unit of each of distance, radius, and centralthickness is millimeter (mm):

f: the focal length of the imaging lens assembly LA;

f1: the focal length of the first lens L1;

f2: the focal length of the second lens L2;

f3: the focal length of the third lens L3;

f4: the focal length of the fourth lens L4;

f5: the focal length of the fifth lens L5;

f6: the focal length of the sixth lens L6;

Fno: F-number; 2ω: full view angle;

S1: aperture stop;

R: the curvature radius of an optical surface, and may also be thecentral curvature radius of the lens;

R1: the curvature radius of the object side of the first lens L1;

R2: the curvature radius of the image side of the first lens L1;

R3: the curvature radius of the object side of the second lens L2;

R4: the curvature radius of the image side of the second lens L2;

R5: the curvature radius of the object side of the third lens L3;

R6: the curvature radius of the image side of the third lens L3;

R7: the curvature radius of the object side of the fourth lens L4;

R8: the curvature radius of the image side of the fourth lens L4;

R9: the curvature radius of the object side of the fifth lens L5;

R10: the curvature radius of the image side of the fifth lens L5;

R11: the curvature radius of the object side of the sixth lens L6;

R12: the curvature radius of the image side of the sixth lens L6;

R13: the curvature radius of the object side of the glass filter GF;

R14: the curvature radius of the image side of the glass filter GF;

d: an axial thickness of the lens or an axial distance between lenses;

d0: the axial distance between the aperture stop and the object side ofthe first lens L1;

d1: the central thickness of the first lens L1;

d2: the axial distance between the image side of the first lens L1 andthe object side of the second lens L2;

d3: the central thickness of the second lens L2;

d4: the axial distance between the image side of the second lens L2 andthe object side of the third lens L3;

d5: the central thickness of the third lens L3;

d6: the axial distance between the image side of the third lens L3 andthe object side of the fourth lens L4;

d7: the central thickness of the fourth lens L4;

d8: the axial distance between the image side of the fourth lens L4 andthe object side of the fifth lens L5;

d9: the central thickness of the fifth lens L5;

d10: the axial distance between the image side of the fifth lens L5 andthe object side of the sixth lens L6;

d11: the central thickness of the sixth lens L6;

d12: the axial distance between the image side of the sixth lens L6 andthe object side of the glass filter GF;

d13: the central thickness of the glass filter GF;

d14: the axial distance between the image side of the glass filter GFand the image plane;

nd: d line refraction index;

nd1: d line refraction index of the first lens L1;

nd2: d line refraction index of the second lens L2;

nd3: d line refraction index of the third lens L3;

nd4: d line refraction index of the fourth lens L4;

nd5: d line refraction index of the fifth lens L5;

nd6: d line refraction index of the sixth lens L6;

nd7: d line refraction index of the glass filter GF;

νd: abbe number (i.e., dispersion coefficient)

ν1: abbe number of the first lens L1;

ν2: abbe number of the second lens L2;

ν3: abbe number of the third lens L3;

ν4: abbe number of the fourth lens L4;

ν5: abbe number of the fifth lens L5;

ν6: abbe number of the sixth lens L6;

ν7: abbe number of the glass plate GF;

TTL: the total track length (i.e., an axial distance between the objectside of the first lens L1 and the image plane);

LB: the axial distance between the image side of the second lens L6 andthe image plane (including a thickness of the glass plate GF); and

IH: the image height.

y=(x ² /R)/[1+{1−(k+1)(x ² /R ²)}^(1/2) ]+A4x ⁴ +A6x ⁶ +A8x ⁸ +A10x ¹⁰+A12x ¹² +A14x ¹⁴ +A16x ¹⁶  (6)

In the above condition (6), R refers to an axial curvature radius, krefers to a conic coefficient, and A4, A6, A8, A10, A12, A14 and A16 areaspherical coefficients.

Optionally, aspherical surfaces of the lenses L1-L6 may be obtainedaccording to condition (6); alternatively, the aspherical surfaces mayalso be obtained according to other conditions.

Embodiment 1

FIG. 2 illustrated an imaging lens assembly LA in accordance with thefirst exemplified embodiment of the present disclosure. TABLE 1 andTABLE 2 show the detailed optical data of the imaging lens assembly LA.

The optical data in TABLE 1 includes the curvature radius R, the axialthickness d, the axial distance between lenses d, refraction index ndand abbe number νd of the lenses L1 to L6 in the imaging lens assemblyLA. The optical data in TABLE 2 includes conic coefficient(C-coefficient) k and aspherical coefficient of the lenses L1 to L6 inthe imaging lens assembly LA.

TABLE 1 R d nd νd S1 ∞ d0 = −0.310 R1 1.53995 d1 = 0.586 nd1 1.5441 ν156.12 R2 22.07678 d2 = 0.058 R3 37.19457 d3 = 0.243 nd2 1.6448 ν2 22.44R4 3.38460 d4 = 0.373 R5 −58.09431 d5 = 0.238 nd3 1.6397 ν3 23.53 R6−92.35499 d6 = 0.080 R7 4.91476 d7 = 0.366 nd4 1.5441 ν4 56.12 R85.21559 d8 = 0.366 R9 −7.46637 d9 = 0.519 nd5 1.5352 ν5 56.12 R10−1.31277 d10 = 0.510 R11 −2.88094 d11 = 0.418 nd6 1.5352 ν6 56.12 R122.42017 d12 = 0.520 R13 ∞ d13 = 0.210 nd7 1.5168 ν6 64.17 R14 ∞ d14 =0.189

TABLE 2 C-coefficient aspherical coefficient k A4 A6 A8 A10 A12 A14 A16R1 −3.3341E−01 1.3666E−03 2.9702E−02 −2.1774E−02 −9.3438E−03 1.5200E−021.3663E−02 −2.5549E−02 R2 0.0000E+00 −2.5760E−02 1.4567E−02 3.6346E−02−3.8835E−02 −5.7498E−02 2.4410E−03 3.5800E−02 R3 −1.3537E+03 −9.8237E−033.2261E−02 2.2134E−02 6.4311E−04 −4.2221E−02 −7.0047E−02 9.4446E−02 R4−2.9129E+00 2.4410E−02 8.8216E−03 9.4199E−02 3.1828E−02 −1.0801E−01−1.3076E−01 1.9366E−01 R5 −4.4128E+02 −2.3399E−02 −6.2691E−02−2.9843E−02 3.2513E−02 4.9103E−02 2.2515E−02 −5.1583E−02 R6 4.8417E+03−2.6769E−02 −7.1330E−02 5.2181E−03 3.6132E−02 2.1292E−02 −2.2877E−04−1.1071E−02 R7 0.0000E+00 −1.3306E−01 1.0505E−02 1.0562E−02 5.7542E−032.2628E−03 −4.7011E−04 −1.2293E−03 R8 0.0000E+00 −1.0952E−01 1.2147E−024.9050E−03 −1.6616E−03 −8.6107E−04 7.5762E−05 1.4271E−04 R9 7.3469E+00−1.8669E−02 −1.2579E−02 2.0484E−03 −1.7373E−03 9.7874E−05 1.9435E−041.2021E−05 R10 −3.7865E+00 −3.5819E−02 1.7662E−02 −1.1281E−03−6.2566E−05 −7.5645E−05 −4.2074E−06 2.8034E−06 R11 0.0000E+00−2.2345E−05 4.0238E−03 5.8035E−05 −2.8897E−05 −2.0160E−06 5.9500E−084.9453E−08 R12 −1.9599E+01 −2.7118E−02 4.0662E−03 −7.5953E−04 3.2209E−051.5758E−06 6.4623E−08 2.7787E−09

The relevant optical data of the imaging lens assembly LA in the firstembodiment and the values defined in the aforesaid conditions (1) to (5)are shown in TABLE 5 as provided in the subsequent paragraphs.

As can be seen in TABLE 5, the imaging lens assembly LA in the firstembodiment satisfies the aforesaid conditions (1) to (5).

FIGS. 3-5 schematically illustrate the longitudinal aberration, thelateral color, the field curvature and distortion of the imaging lensassembly LA as provided in the first embodiment respectively. In FIG. 5,curve S represents the field curvature related to the sagittal plane,and curve T represents the field curvature related to the tangentialplane.

As can be seen, in the first embodiment, the view angle 2ω of theimaging lens assembly LA is 82.8°, the proportion value TTL/IH of theimaging lens assembly LA is 1.346, and the F number is 2.05. In otherwords, the imaging lens assembly LA as provided in the first embodimenthas an ultra-thin profile and a wide-angle with high luminous flux, andaccordingly has good optical characteristics.

Embodiment 2

FIG. 6 illustrated an imaging lens assembly LA in accordance with thesecond embodiment of the present disclosure. TABLE 3 and TABLE 4 showthe detailed optical data of the imaging lens assembly LA.

The optical data in TABLE 3 includes the curvature radius R, the axialthickness d, the axial distance between lenses d, refraction index ndand abbe number νd of the lenses L1 to L6 in the imaging lens assemblyLA. The optical data in TABLE 4 includes conic coefficient(C-coefficient) k and aspherical coefficient of the lenses L1 to L6 inthe imaging lens assembly LA.

TABLE 3 R d nd νd S1 ∞ d0 = −0.310 R1 1.51908 d1 = 0.600 nd1 1.5441 ν156.12 R2 14.33117 d2 = 0.059 R3 34.18880 d3 = 0.240 nd2 1.6448 ν2 22.44R4 3.47890 d4 = 0.377 R5 −61.38130 d5 = 0.242 nd3 1.6397 ν3 23.53 R6−96.57146 d6 = 0.078 R7 4.91934 d7 = 0.372 nd4 1.5441 ν4 56.12 R85.17762 d8 = 0.373 R9 −7.49478 d9 = 0.512 nd5 1.5352 ν5 56.12 R10−1.31517 d10 = 0.506 R11 −2.87700 d11 = 0.414 nd6 1.5352 ν6 56.12 R122.41807 d12 = 0.520 R13 ∞ d13 = 0.210 nd7 1.5168 ν6 64.17 R14 ∞ d14 =0.179

TABLE 4 C-coefficient aspherical coefficient k A4 A6 A8 A10 A12 A14 A16R1 −4.0088E−01 −3.6777E−03 2.8909E−02 −2.1526E−02 −9.0835E−03 1.5311E−021.3637E−02 −2.5670E−02 R2 0.0000E+00 −3.7770E−02 1.0818E−02 3.5228E−02−3.8826E−02 −5.6957E−02 3.2369E−03 3.6712E−02 R3 1.6578E+01 −8.8559E−033.1152E−02 2.1504E−02 1.9774E−04 −4.2649E−02 −7.0497E−02 9.3977E−02 R4−2.4633E+00 2.7059E−02 2.1201E−02 9.8279E−02 3.1597E−02 −1.0982E−01−1.3285E−01 1.9187E−01 R5 −7.6696E+03 −2.0749E−02 −6.0434E−02−2.9271E−02 3.2567E−02 4.9881E−02 2.4601E−02 −4.7741E−02 R6 5.0291E+03−2.6963E−02 −7.2019E−02 4.9280E−03 3.6069E−02 2.1300E−02 −1.8706E−04−1.1035E−02 R7 0.0000E+00 −1.3337E−01 1.0544E−02 1.0671E−02 5.8292E−032.3010E−03 −4.5915E−04 −1.2376E−03 R8 0.0000E+00 −1.0851E−01 1.2129E−024.7722E−03 −1.7231E−03 −8.8050E−04 7.1875E−05 1.4344E−04 R9 7.7607E+00−1.8893E−02 −1.2732E−02 1.9952E−03 −1.7485E−03 9.3804E−05 1.9170E−041.0511E−05 R10 −3.7863E+00 −3.5794E−02 1.7648E−02 −1.1418E−03−6.7872E−05 −7.6966E−05 −4.3165E−06 2.9216E−06 R11 0.0000E+00−9.3462E−05 4.0190E−03 5.7923E−05 −2.8853E−05 −2.0041E−06 6.2658E−085.0407E−08 R12 −2.0452E+01 −2.7121E−02 4.0868E−03 −7.5667E−04 3.2432E−051.5889E−06 6.4978E−08 2.6980E−09

The relevant optical data of the imaging lens assembly LA in the secondembodiment and the values defined in the aforesaid conditions (1) to (5)are shown in TABLE 5 as provided in the subsequent paragraphs. As can beseen in TABLE 5, the imaging lens assembly LA in the second embodimentsatisfies the aforesaid conditions (1) to (5).

FIGS. 7-9 schematically illustrate the longitudinal aberration, thelateral color, the field curvature and distortion of the imaging lensassembly LA as provided in the second exemplified embodimentrespectively. In FIG. 9, curve S represents the field curvature relatedto the sagittal plane, and curve T represents the field curvaturerelated to the tangential plane.

As can be seen, in the second exemplified embodiment, the view angle 2ωof the imaging lens assembly LA is 82.6°, the proportion value TTL/IH ofthe imaging lens assembly LA is 1.347, and the F number is 2.05. Inother words, the imaging lens assembly LA as provided in the secondembodiment has an ultra-thin profile and a wide-angle with high luminousflux, and accordingly has good optical characteristics.

TABLE 5 shows the values of the imaging lens assembly LA in relevant tothe conditions (1) to (5) according to both the first embodiment and thesecond embodiment. Moreover, in TABLE 5, the unit of the value 2ω isdegree (°), and the units of the values f, f1, f2, f3, f4, f5, f6, TTL,LB and IH are millimeter (mm).

TABLE 5 Embodiment 1 Embodiment 2 Formulae f1/f 0.78 0.79 Formula (1)(R1 + R2)/(R1 − R2) −1.15 −1.24 Formula (2) (R3 + R4)/(R3 − R4) 1.201.23 Formula (3) (R5 + R6)/(R5 − R6) −4.39 −4.49 Formula (4) f2/f −1.49−1.54 Formula (5) Fno 2.05 2.05 2ω 82.8 82.6 TTL/IH 1.346 1.347 f 3.8743.906 f1 3.012 3.072 f2 −5.791 −6.025 f3 −245.459 −264.018 f4 109.613120.227 f5 2.891 2.897 f6 −2.392 −2.390 TTL 4.676 4.682 LB 0.919 0.909IH 3.475 3.475

In summary, the imaging lens assembly LA as provided in the presentdisclosure has good optical characteristic, high luminous flux as wellas an ultra-thin profile, and moreover, the imaging lens assembly LAsatisfies the following parameter requirements: TTL/IH≦1.35, view angle2ω≧76°, and Fno≦2.2. Therefore, the imaging lens assembly LA isapplicable to a digital camera of a mobile phone or a WEB camera, whichuses CCD imaging components or CMOS imaging components with highresolution.

It is to be understood, however, that even though numerouscharacteristics and advantages of the present embodiment have been setforth in the foregoing description, together with details of thestructures and functions of the embodiment, the disclosure isillustrative only, and changes may be made in detail, especially inmatters of shape, size, and arrangement of parts within the principlesof the invention to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed.

What is claimed is:
 1. An imaging lens assembly, comprising: a firstlens with positive refractive power; a second lens with negativerefractive power; a third lens with negative refractive power; a fourthlens with positive or negative refractive power; a fifth lens withpositive refractive power; and a sixth lens with negative refractivepower; wherein the first lens, the second lens, the third lens, thefourth lens, the fifth lens and the sixth lens are arranged in sequencefrom the object side to the image side, and satisfy the followingconditions (1) to (4):0.60≦f1/f≦0.80  (1)−2.00≦(R1+R2)/(R1−R2)≦−1.10  (2)1.15≦(R3+R4)/(R3−R4)≦1.40  (3)−7.50≦(R5+R6)/(R5−R6)≦−3.00  (4) wherein f is the focal length of theimaging lens assembly; f1 is the focal length of the first lens; R1 isthe curvature radius of the object side of the first lens; R2 is thecurvature radius of the image side of the first lens; R3 is thecurvature radius of the object side of the second lens; R4 is thecurvature radius of the image side of the second lens; R5 is thecurvature radius of the object side of the third lens; R6 is thecurvature radius of the image side of the third lens.
 2. The imaginglens assembly of claim 1, further satisfying the following condition(5):−2.00≦f2/f≦−1.00  (5) wherein f is the focal length of the imaging lensassembly, and f2 is the focal length of the second lens.